A continuing problem associated with the spray application of liquid paints is the presence of foreign particulate matter in the liquid paint supply which causes imperfections on the surfaces of an article being spray painted frequently necessitating a refinishing and repainting thereof. Such foreign particulate matter sometimes referred to as "seeds", or "strings", or "slugs" are formed in many instances as a result of an agglomeration of the paint constituents during standing or recirculation of the liquid paint necessitating removal prior to discharge through the spray nozzle. The foregoing problem is particularly pronounced in recirculating-type liquid paint systems which are in widespread commercial use for keeping heavily-bodied pigments uniformly suspended in the liquid paint thereby assuring uniformity in the color and quality of the paint film applied to an article being painted. Such recirculating paint systems usually comprise a mixing tank equipped with suitable agitation for maintaining the paint uniformly mixed and a pump for transferring the liquid paint under a desired pressure to an automatic or manual spray nozzle in an amount in excess of that required which is returned through a suitable return conduit to the mixing tank. In spite of the provision of suitable filters in the recirculating supply line, the accumulation of foreign particulate matter occurs resulting in objectionable spray patterns.
The foregoing problem is also encountered during the spray application of paints supplied from a suction tank or cup directly connected to the spray gun. In recognition of this problem, a variety of filter devices have heretofore been proposed or used in liquid paint supply systems which are adapted to be connected at a point in close proximity to the spray nozzle effecting a final filtration just prior to entry of the spray assembly. Prior art filter assemblies of the types heretofore known are generally characterized by their relatively large size and associated weight, by their multiple component construction increasing the complexity and cost of the assembly as well as difficulty during cleaning and replacement of the filter cartridges, and their relatively large volume requiring increased time to effect a purging of the internal volume thereof such as occasioned when changing paint colors in a multiple-color recirculating paint supply system. Such prior art filter assemblies because of their size and weight have not received widespread commercial acceptance in hand-held paint spray systems due to the awkwardness of the resulting assembly.
The present invention overcomes many of the problems and disadvantages associated with prior art filter assemblies by providing a compact, simple, lightweight and highly efficient inline filter assembly which is versatile in use and can be installed at any one of a variety of locations in a liquid paint supply system. The compact and simple construction of the filter assembly enables attachment directly to a hand-held spray gun without materially increasing the weight of the assembly as well as to automatic spray equipment. The simplicity and efficiency of the filter assembly facilitates periodic cleaning of the filtering element thereof and provides for a low cost simple and efficient assembly.